Purpose is to study the process of learning compensatory speech patterns, when a dental appliance causes speech interference. Acoustical analysis of speech, and physiological measures of jaw motions, larynx position and vocal fold activity, and timing and location of tongue-palate contact will be made. Normal volunteers will wear experimental alveolar-palatal prostheses for a period of several weeks, and data on speech characteristics will be obtained before, during, and after speech adaptation.